MSL: Add test for scalar access chain pull interpolant.

reference/shaders-msl-no-opt/frag/pull-interpolant-access-chain.msl23.frag

@@ -0,0 +1,75 @@
+#pragma clang diagnostic ignored "-Wmissing-prototypes"
+#pragma clang diagnostic ignored "-Wmissing-braces"
+
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+template<typename T, size_t Num>
+struct spvUnsafeArray
+{
+    T elements[Num ? Num : 1];
+    
+    thread T& operator [] (size_t pos) thread
+    {
+        return elements[pos];
+    }
+    constexpr const thread T& operator [] (size_t pos) const thread
+    {
+        return elements[pos];
+    }
+    
+    device T& operator [] (size_t pos) device
+    {
+        return elements[pos];
+    }
+    constexpr const device T& operator [] (size_t pos) const device
+    {
+        return elements[pos];
+    }
+    
+    constexpr const constant T& operator [] (size_t pos) const constant
+    {
+        return elements[pos];
+    }
+    
+    threadgroup T& operator [] (size_t pos) threadgroup
+    {
+        return elements[pos];
+    }
+    constexpr const threadgroup T& operator [] (size_t pos) const threadgroup
+    {
+        return elements[pos];
+    }
+};
+
+struct main0_out
+{
+    float4 FragColor [[color(0)]];
+};
+
+struct main0_in
+{
+    interpolant<float4, interpolation::perspective> a_0 [[user(locn0)]];
+    interpolant<float4, interpolation::perspective> a_1 [[user(locn1)]];
+    interpolant<float4, interpolation::perspective> b_0 [[user(locn2)]];
+    interpolant<float4, interpolation::perspective> b_1 [[user(locn3)]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]])
+{
+    main0_out out = {};
+    spvUnsafeArray<float4, 2> a = {};
+    spvUnsafeArray<float4, 2> b = {};
+    a[0] = in.a_0.interpolate_at_centroid();
+    a[1] = in.a_1.interpolate_at_centroid();
+    b[0] = in.b_0.interpolate_at_centroid();
+    b[1] = in.b_1.interpolate_at_centroid();
+    out.FragColor.x = in.a_0.interpolate_at_offset(float2(0.5) + 0.4375).x;
+    out.FragColor.y = in.a_1.interpolate_at_offset(float2(0.5) + 0.4375).y;
+    out.FragColor.z = in.b_0.interpolate_at_offset(float2(0.5) + 0.4375).z;
+    out.FragColor.w = in.b_1.interpolate_at_offset(float2(0.5) + 0.4375).w;
+    return out;
+}
+

shaders-msl-no-opt/frag/pull-interpolant-access-chain.msl23.frag

@@ -0,0 +1,12 @@
+#version 450
+layout(location = 0) centroid in vec4 a[2];
+layout(location = 2) centroid in vec4 b[2];
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+	FragColor.x = interpolateAtOffset(a[0].x, vec2(0.5));
+	FragColor.y = interpolateAtOffset(a[1].y, vec2(0.5));
+	FragColor.z = interpolateAtOffset(b[0].z, vec2(0.5));
+	FragColor.w = interpolateAtOffset(b[1].w, vec2(0.5));
+}